Grinding machine for household use

ABSTRACT

A machine comprising a rotary shaft rotatably supported by a housing in an axially displaceable manner; a whetstone mounted on one end of the rotary shaft and having an exposed abrasive surface; an impeller mounted on the rotary shaft within the housing and having a number of blades resembling turbine blades; a nozzle positioned diametrically inside the blades and having a plurality of jet openings for forcing water against the blades substantially perpendicular thereto; and rotating the turbine and blades means for supplying tap water to the nozzle; and means for urging the rotary shaft axially thereof in counteracting relation to the pressure exerted on the abrasive surface by an article to be sharpened, the pressure of the tap water forced from the nozzle rotating the whetstone, the article is urged into contact with the whetstone under a proper pressure.

United States Patent Ise GRINDING MACHINE FOR HOUSEHOLD USE Inventor: Minoru Ise, Osaka, Japan Ise Kogyo Kabushiki Kaisha, Osaka, Japan Filed: May 24, 1974 Appl. No.: 473,181

Assignee:

Foreign Application Priority Data June 1, 1973 Japan 48-65391 US. Cl. 51/109 R; 51/128; 51/l34.5 F Int. Cl. B29B 3/36 Field of Search 51/l34.5 F, 109, 128

11/1957 Middlemark. 51/109 X Powell 51/l34.5

Primary ExaminerHarold D. Whitehead Attorney, Agent, or Firm-I-lolman & Stern [57] ABSTRACT A machine comprising a rotary shaft rotatably supported by a housing in an axially displaceable manner; a Whetstone mounted on one end of the rotary shaft and having an exposed abrasive surface; an impeller mounted on the rotary shaft within the housing and having a number of blades resembling turbine blades; a nozzle positioned diametrically inside the blades and having a plurality of jet openings for forcing water against the blades substantially perpendicular thereto; and rotating the turbine and blades means for supplying tap water to thenozzle; and means for urging the rotary shaft axially thereof in counteracting relation to the pressure exerted on the abrasive surface by an article to be sharpened, the pressure of the tap water forced from the nozzle rotating the Whetstone, the article is urged into contact with the Whetstone under a proper pressure.

4 Claims, 6 Drawing Figures US. Patent 01:1. 14, 1975 Sheet 1 Of3 3,911,625

Fig.2

US. Patent Oct. 14, 1975 Sheet 2 of 3 3,911,625

U.S. Patent 0a. 14, 1975 Sheet 3 on 3,911,625

Fig.6

GRINDING MACHINE FOR HOUSEHOLD USE BACKGROUND OF THE INVENTION The present invention relates to a grinding machine for household use, more particularly to a grinding machine in which the Whetstone is driven by the hydraulic pressure of tap water to sharpen kitchen knives and like cutlery or hand tools for household use.

When sharpening household knives and hand tools on an electric grinder, it is dangerous to apply tap water to the abrasive member because of the possible leak of electric current. Such problem can be easily eliminated if the Whetstone is adapted to be driven by the hydraulic pressure of tap water. However, a machine in which i the hydraulic pressure is utilized, merely to drive the Whetstone, still need be given a special consideration to make it easier to operate since, as a household device, it is frequently used by an unskilled person. Especially, it is noted that the contact pressure between the whetstone and the implement to be sharpened is critical.

SUMMARY OF THE INVENTION An object of this invention is to provide a grinding machine for household use which is designed to be driven by the hydraulic pressure of tap water and which is operable very easily even by those having almost no experience in handling machines.

Another object of this invention is to provide a machine in which the article to be sharpened can be held in contact with the Whetstone under a proper pressure during grinding operation, irrespective of whether or not the article is properly pressed against the whetstone.

To fulfill these objects, the present invention provides a grinding machine for household use comprising a housing adapted to be installed, for example, on the sink or in some other place convenient for grinding, a rotary shaft rotatably supported by the housing in an axially movable manner, a Whetstone mounted on one end of the rotary shaft projecting outward from the housing and having its abrasive surface exposed from the housing, an impeller mounted on the rotary shaft within the housing and having a number of vertical blades along its outer periphery, a nozzle positioned diametrically inside the blades of the impeller and having a plurality of jet openings for forcing water against the blades substantially perpendicular thereto, water supply means to be connected to a water supply faucet for supplying tap water to the nozzle and means for urging the rotary shaft axially thereof in counteracting relation to the pressure exerted on the abrasive surface by an article to be sharpened.

When tap water is supplied to the nozzle, the pressure of the water forced out from the nozzle drives the impeller, causing the rotary shaft to rotate the whet stone to sharpen the article pressed against the abrasive surface. By adjusting the supply of tap water, namely the opening degree of the faucet, the pressure of the water forced out from the nozzle is varied, whereby the torque and speed of rotation of the Whetstone can be changed as desired. The water jetted out from the nozzle strikes the blades of the impeller substantially perpendicular thereto, making it possible to utilize the hydraulic pressure very efficiently to give a sufficient torque to the Whetstone.

On the other hand, the force acting on the rotary shaft to urge the same in its axial direction counteracts the pressing force exerted by the article on the abrasive surface to give a proper contact pressure all the time, thereby assuring a satisfactory grinding operation irrespective of whether or not the article is properly pressed against the Whetstone. Since there is no need to provide a special thrust bearing at the end of the rotary shaft to receive the pressing force, the construction for supporting the rotary shaft can be simplified.

Other objects and features of this invention will become more apparent from the following description.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front view partly broken away and showing an embodiment of this invention;

FIG. 2 is a view in section taken along the line IIII to show the relationship between the nozzle and impeller;

FIG. 3 is a view in vertical section showing the details of the means for urging the rotary shaft in its axial direction;

FIG. 4 is a view in vertical section of another embodiment;

FIG. 5 is a view in vertical section of another embodiment; and

FIG. 6 is a view in vertical section of still another embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS With reference to FIG. 1, there is shown a housing 10 having three or four legs 1 l for supporting the machine on a sink or suitable place. The housing 10 includes bearing portions 12 and 13 rotatably supporting a rotary shaft 14. The shaft 14 is axially movable within a limited range. A Whetstone 15 is removably mounted, by a screw 16 or the like, on one end of the rotary shaft 14 which end projects outward from the housing 10.

Fixedly mounted on the rotary shaft 14 at a portion thereof within the housing is an impeller 18 having a number of vertical blades 17 resembling turbine blades and arranged on the same circumference at its outer periphery. A noule 20 disposed diametrically inward of the blades 17 has a plurality of jet openings 19 for forcing out water against the surfaces of the blades 17 substantially perpendicular thereto. As seen in FIGS. 1 and 2, the nozzle 20 is fixed to the housing 10 and has a central uniform pressure chamber 21, around which the jet openings 19 are formed. The uniform pressure chamber 21 communicates with a connecting tube 22 for supplying water. The connecting tube 22 is adapted to be connected to an unillustrated faucet for water supply by an unillustrated rubber hose or the like. Indicated at 27 is a drain opening.

The bottom of the bearing 12 is formed with a small bore 23 communicating with the uniform pressure chamber 21, such that the pressure of the water within the chamber 21 will act on the lower end of the rotary shaft 14 through a movable member 24 and a ball 25 which are disposed in the bottom of the bearing portion 12 to urge the shaft 14 axially thereof in counteracting relation to the pressing force exerted on the abrasive surface by an article to be sharped. As seen in FIG. 3, a sleeve 26 may be provided in the bearing portion 12. The sleeve is movable relative to the rotary shaft 14 and to the inner surface of the bearing portion 12 to reduce the frictional force to be involved in the rotation and axial movement of the rotary shaft 14. The axial movement of the rotary shaft 14 is limited to a specified range by the bearing portions 12 and 13, whereby the shaft is prevented from being forced out from the housing 10.

When water is supplied from the faucet to the connecting tube 22 through the interconnecting rubber hose or the like, the water jets out from the openings 19 and strikes the blades 17 to drive the impeller 18, which in turn rotates the whetstone by way of the rotary shaft 14. The amount of water supplied to the nozzle 20 is variable as desired by adjusting the opening degree of the faucet. Accordingly, the pressure of water within the chamber 21 is variable to control the torque and speed of rotation of the whetstone 15 as desired. Since electric power is not used at all, there is no danger of a current short.

The hydraulic pressure of the chamber 21 urges the rotary shaft 14 in its axial direction through the bore 23, movable member 24 and ball 25 and raises the whetstone 15. The urging force counteracting the pressing force exerted by the article on the abrasive surface maintains them in contact with each other under a proper pressure to assure the desired grinding operation, whether the article is pressed against the abrasive surface properly or not. The ball 25 serves to mitigate the frictional resistance between the rotary shaft 14 and the bearing portion 12 during the rotation of the shaft 14.

FIG. 4 shows a more simplified grinding machine for household use. A housing having three or four legs 41 has bearing portions 42 and 43 which rotatably support a rotary shaft 44 in axially movable manner. The shaft 44 is provided with a whetstone 45 at its one end and fixedly carries an impeller 48 within the housing 40. The impeller 48 has blades 47 resembling turbine blades. The shaft 44 is driven by the water forced out from the jet openings 50 of a nozzle 20. The pressure of water within a uniform pressure chamber 51 acts on the shaft 44 through a small bore 53 formed in the bottom of the bearing portion 42 and urges the shaft in its axial direction to maintain a proper contact pressure between the article to be sharpened and the abrasive surface, counteracting the pressing force of the article acting on the whetstone. Indicated at 52 is a connecting tube for supplying water.

In brief, the movable member 24 and ball 25 shown in FIG. 1 are eliminated in the embodiment of FIG. 4 to simplify the overall construction.

The means for urging the rotary shaft 44 in FIG. 4 is modified in the embodiment shown in FIG. 5. The jet openings 49 of a nozzle 50 extend obliquely upward, and an impeller 58 has an umbrella-like slanting portion 59 at its periphery. The water forced out from the jet opening 49 strikes the blades 47 and also the slanting portion 59 at the same time. A component of the striking force urges the rotary shaft 44 in counteracting relation to the pressing force exerted on the abrasive surface by the article to be sharpened.

As shown in FIG. 6, the rotary shaft 44 may altematively be urged by a coiled spring 60 or like biasing means housed in the bearing portion 42. Such means may also be incorporated in the embodiments already described.

FIGS. 5 and 6, the same parts as those in FIG. 4 are referred to by the same reference numerals.

What is claimed is:

1. A grinding machine for household use comprising: a housing to be installed in a desired place, a rotary shaft rotatably supported by the housing in an axially displaceable manner,

a whetstone mounted on one end of the rotary shaft and having an exposed abrasive surface, an impeller fixedly mounted on the rotary shaft within the housing and having a number of blades along its outer periphery, a nozzle positioned diametrically inside the blades of the impeller and having a plurality of jet openings for forcing water against the blades substantially perpendicular thereto, means for supplying tap water to the nozzle, a uniform pressure chamber provided between the nozzle and the tap water supply means, and

means for urging the rotary shaft axially thereof in counteracting relation to the pressing force exerted on the abrasive surface by an article to be sharpened, said urging means including means directing pressure of said tap water from said pressure chamber toward part of the rotary shaft carrying the impeller.

2. The grinding machine as set forth in claim 1 wherein the urging means is provided by the pressure of water in a uniform pressure chamber of the nozzle applied on the other end of the rotary shaft through a small bore communicating with the chamber.

3. The grinding machine as set forth in claim 1 wherein the urging means is provided by a component of striking force of water forced out from the jet openings of the nozzle against the impeller to urge the rotary shaft.

4. The grinding machine as set forth in claim 1 wherein the urging means is a spring biasing the rotary shaft axially thereof. 

1. A grinding machine for household use comprising: a housing to be installed in a desired place, a rotary shaft rotatably supported by the housing in an axially displaceable manner, a whetstone mounted on one end of the rotary shaft and having an exposed abrasive surface, an impeller fixedly mounted on the rotary shaft within the housing and having a number of blades along its outer periphery, a nozzle positioned diametrically inside the blades of the impeller and having a plurality of jet openings for forcing water against the blades substantially perpendicular thereto, means for supplying tap water to the nozzle, a uniform pressure chamber provided between the nozzle and the tap water supply means, and means for urging the rotary shaft axially thereof in counteracting relation to the pressing force exerted on the abrasive surface by an article to be sharpened, said urging means including means directing pressure of said tap water from said pressure chamber toward part of the rotary shaft carrying the impeller.
 2. The grinding machine as set forth in claim 1 wherein the urging means is provided by the pressure of water in a uniform pressure chamber of the nozzle applied on the other end of the rotary shaft through a small bore communicating with the chamber.
 3. The grinding machine as set forth in claim 1 wherein the urging means is provided by a component of striking force of water forced out from the jet openings of the nozzle against the impeller to urge the rotary shaft.
 4. The grinding machine as set forth in claim 1 wherein the urging means is a spring biasing the rotary shaft axially thereof. 